Polyclonal vs Monoclonal Antibodies – Making the Right Choice

Monoclonal or Polyclonal?
The decision of whether a monoclonal or polyclonal antibody is more suitable for a specific research application is determined by a number of factors, and involves comparing the respective attributes of these two kinds of antibodies in light of experimental conditions and demands. In general, monoclonals provide higher specificity while polyclonals provide higher sensitivity. For applications such as Western blotting and immunoprecipitation, polyclonal antibodies often provide a stronger signal. Monoclonals, on the other hand, generally exhibit lower non-specific binding and lower cross-reactivity with other proteins. Once a hybridoma line has been established, monoclonals can be produced in theoretically unlimited quantities. They do, however, require a more complex and lengthy development process than polyclonals.

What is a Polyclonal Antibody?
The term Polyclonal Antibody refers to mixture of antibodies, each produced from different B cells. This is the product of the natural process of exposing a foreign antigen to the immune system of a living organism. The collection of antibodies recognizes multiple epitopes on the same antigen, ensuring efficient capture of the target. Each of the individual antibodies in a polyclonal antibody recognizes a unique epitope that is located on that antigen.

• Inexpensive to produce, and shorter timeline production (3~4 months).
• Stable for longer periods of time when stored at -20 degrees C.
• Recognition of multiple epitopes leads to robust detection on multiple matrices and assay types.
• Potential for better detection of low abundance proteins since multiple antibodies will bind to multiple epitopes on the protein, amplifying the signal.
• Superior for detecting slight variations in individual epitopes due to processes such as denaturation, polymorphism or conformational changes.
• Much easier to couple with antibody labels.

• Lot to lot variability due to unique immunological reaction of individual production animals when exposed to the same antigen.
• Higher potential for cross reactivity/lowered specificity due to recognition of multiple epitopes that may appear in different proteins.
• Affinity purification of the serum may minimize cross reactivity, but leads to loss in yield (upwards of 80%) and costs substantially more (additional columns and resins and labor).

What is a Monoclonal Antibody?
By way of contrast to polyclonal antibodies, production of a monoclonal ready for reagent use is not a natural process, but rather entails an in vitro laboratory procedure whereby the desired B-cell is isolated from an animal and fused to an immortal hybridoma cell line so that large quantities of identical antibody can be generated.

• Large quantities of identical antibody can be produced in bioreactors, with batch to batch homogeneity.
• High specificity to a single definable epitope, and negligible to no cross-reactivity
• High resolving power between small changes in protein target (point mutations, posttranslational modifications, etc.).
• Specificity permits quantitative assays.

• Significantly more expensive to produce.
• First run generation and production time is substantially longer. Must screen large number of clones to find one suitable for desired assay and function.
• Clones must be stored at -80 degrees C.
• Cell culture and purification competencies are required for production and regeneration.
• More sensitive to pH and buffer conditions.
• More susceptible to binding changes when labeled.

For diagnostic and therapeutic applications that demand large volumes of identical antibody specific to a single epitope, monoclonal antibodies are the overwhelmingly preferred option. For general research applications, however, the advantages of polyclonal antibodies often provide the most economical and practical solution.